CN108286968B - Method and device for tracing back ray - Google Patents
Method and device for tracing back ray Download PDFInfo
- Publication number
- CN108286968B CN108286968B CN201710016359.1A CN201710016359A CN108286968B CN 108286968 B CN108286968 B CN 108286968B CN 201710016359 A CN201710016359 A CN 201710016359A CN 108286968 B CN108286968 B CN 108286968B
- Authority
- CN
- China
- Prior art keywords
- plane
- determining
- space
- network element
- reflecting surfaces
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/20—Instruments for performing navigational calculations
- G01C21/206—Instruments for performing navigational calculations specially adapted for indoor navigation
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Automation & Control Theory (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Image Generation (AREA)
Abstract
The invention discloses a method and a device for tracing back rays, wherein the method comprises the following steps: determining effective reflecting surfaces in all reflecting surfaces in a preset indoor space according to a preset rule, wherein the effective reflecting surfaces are reflecting surfaces capable of reflecting; and determining the position of the terminal to be positioned based on all the effective reflecting surfaces according to a reverse ray tracing algorithm and a virtual mirror image point algorithm. The effective reflecting surfaces in all the reflecting surfaces in the preset indoor space are determined according to the preset rule, and then calculation and processing are carried out based on all the effective reflecting surfaces, so that the number of the reflecting surfaces to be tracked in the preset space is greatly reduced, the calculation amount is greatly reduced, the ray tracking efficiency is improved, and the following problems in the prior art are solved: when the inverse ray tracing algorithm is implemented, the calculation process is very complex and the ray tracing efficiency is low due to the fact that the number of planes in the space is large.
Description
Technical Field
The invention relates to the field of positioning, in particular to a method and a device for tracing a reverse ray.
Background
With the development of network technology and communication technology, location service becomes increasingly important, people can find destination places very easily in strange cities, and can obtain service recommendation based on locations at any time, so that huge social benefits and economic benefits are generated. At present, more and more application demands are required, and accurate position services such as gift position pushing of airport shops, automatic parking of underground garages and the like can be obtained indoors and outdoors.
Currently, there are two main approaches for indoor positioning: one is a statistical model, and the signal intensity derived from the statistical analysis of a large amount of measurement data obeys a certain distribution indoors, but one propagation model only corresponds to a specific environment and cannot be applied to other environments.
The other method is a ray tracing method, which analyzes the signal intensity in the space by simulating the propagation path of the ray based on the geometrical optics theory. The reverse ray tracing algorithm is the most common ray tracing method, and the algorithm regards all objects in the space as being formed by planes, a curved surface can be approximately assembled by a plurality of planes, secondly, taking secondary reflection as an example, a network element (a primary node) makes mirror image points (secondary nodes) about all the planes, if N planes exist, N secondary original points are generated, and then the N secondary original points make mirror image points about the N planes again, and then N multiplied by N secondary mirror image points are generated.
In the implementation process, starting from the receiving point, each path which can reach the receiving point from the source point is traced backwards. But when considering multiple reflections, such as more than 5 times, the calculation process is very complicated due to the need to traverse each plane in space, and the ray tracing efficiency is low due to the many planes in space.
Disclosure of Invention
The invention provides a method and a device for tracing a reverse ray, which are used for solving the following problems in the prior art: when the inverse ray tracing algorithm is implemented, the calculation process is very complex and the ray tracing efficiency is low due to the fact that the number of planes in the space is large.
To solve the above technical problem, in one aspect, the present invention provides a method for back ray tracing, including: determining an effective reflecting surface in all reflecting surfaces in a preset indoor space according to a preset rule, wherein the effective reflecting surface is a reflecting surface capable of reflecting; and determining the position of the terminal to be positioned based on all the effective reflecting surfaces according to a reverse ray tracing algorithm and a virtual mirror image point algorithm.
Optionally, determining an effective reflecting surface of all reflecting surfaces in the predetermined indoor space according to a predetermined rule includes: judging whether other intersection points with the first predetermined object exist between line segments connected with the center point of the predetermined plane of the first predetermined object; and under the condition that other intersection points do not exist, determining the plane where the central point is located as an effective reflecting surface.
Optionally, the determining whether there are other intersection points with the first predetermined object between the line segments connected between the network element and the center point of the predetermined plane of the first predetermined object includes: establishing a space rectangular coordinate system for a preset indoor space; determining the space coordinates of the network element, the space coordinates of each vertex included in each plane of the first predetermined object and the plane equation of each plane of the first predetermined object in the established space rectangular coordinate system; determining the spatial coordinates of the central point corresponding to each plane according to the spatial coordinates of each vertex of each plane; establishing a linear equation of the central point and the network element according to the spatial coordinate of the central point and the spatial coordinate of the network element; and judging whether other intersection points with the first preset object exist on a line segment corresponding to the linear equation where the central point and the network element are located.
Optionally, the method further includes: judging whether the plane equation of each plane of the first predetermined object and the plane equation of each plane of the second predetermined object have the same plane equation or not; under the condition that the same plane equation exists, acquiring respective vertex space coordinates of two planes with the same plane equation; judging whether the space coordinates of each vertex of the effective reflecting surfaces in the two planes are in the range of the space coordinates of each vertex of the other plane; and under the condition that each vertex space coordinate of the effective reflecting surface is in the range of each vertex space coordinate of the other plane, the effective reflecting surface is determined as an ineffective reflecting surface again.
Optionally, determining the position of the terminal to be positioned based on all the effective reflecting surfaces according to a back ray tracing algorithm and a virtual mirror image point algorithm, includes: determining a plurality of reflection paths between the terminal to be positioned and each network element according to each effective reflection surface in sequence according to a virtual mirror image point algorithm; synthesizing a plurality of reflection paths between each network element and the terminal to be positioned into a synthesized reflection path according to a preset synthesis algorithm; and under the condition that the terminal to be positioned has four synthesized reflection paths, determining the position of the terminal to be positioned according to the network element positions corresponding to the four synthesized reflection paths by a back ray tracing algorithm.
In another aspect, the present invention further provides an inverse ray tracing apparatus, including: the device comprises a determining module, a judging module and a judging module, wherein the determining module is used for determining effective reflecting surfaces in all reflecting surfaces in a preset indoor space according to a preset rule, and the effective reflecting surfaces are reflecting surfaces which can be reflected; and the positioning module is used for determining the position of the terminal to be positioned based on all the effective reflecting surfaces according to a reverse ray tracing algorithm and a virtual mirror image point algorithm.
Optionally, the determining module is specifically configured to: judging whether other intersection points with the first predetermined object exist between line segments connected with the center point of the predetermined plane of the first predetermined object; and under the condition that other intersection points do not exist, determining the plane where the central point is located as an effective reflecting surface.
Optionally, the determining module is specifically configured to: establishing a space rectangular coordinate system for a preset indoor space; determining the space coordinates of the network element, the space coordinates of each vertex included in each plane of the first predetermined object and the plane equation of each plane of the first predetermined object in the established space rectangular coordinate system; determining the spatial coordinates of the central point corresponding to each plane according to the spatial coordinates of each vertex of each plane; establishing a linear equation of the central point and the network element according to the spatial coordinate of the central point and the spatial coordinate of the network element; and judging whether other intersection points with the first preset object exist on a line segment corresponding to the linear equation where the central point and the network element are located.
Optionally, the determining module is further configured to: judging whether the plane equation of each plane of the first predetermined object and the plane equation of each plane of the second predetermined object have the same plane equation or not; under the condition that the same plane equation exists, acquiring respective vertex space coordinates of two planes with the same plane equation; judging whether the space coordinates of each vertex of the effective reflecting surfaces in the two planes are in the range of the space coordinates of each vertex of the other plane; and under the condition that each vertex space coordinate of the effective reflecting surface is in the range of each vertex space coordinate of the other plane, the effective reflecting surface is determined as an ineffective reflecting surface again.
Optionally, the positioning module is specifically configured to: determining a plurality of reflection paths between the terminal to be positioned and each network element according to each effective reflection surface in sequence according to a virtual mirror image point algorithm; synthesizing a plurality of reflection paths between each network element and the terminal to be positioned into a synthesized reflection path according to a preset synthesis algorithm; and under the condition that the terminal to be positioned has four synthesized reflection paths, determining the position of the terminal to be positioned according to the network element positions corresponding to the four synthesized reflection paths by a back ray tracing algorithm.
The effective reflecting surfaces in all the reflecting surfaces in the preset indoor space are determined according to the preset rule, and then calculation and processing are carried out based on all the effective reflecting surfaces, so that the number of the reflecting surfaces to be tracked in the preset space is greatly reduced, the calculation amount is greatly reduced, the ray tracking efficiency is improved, and the following problems in the prior art are solved: when the inverse ray tracing algorithm is implemented, the calculation process is very complex and the ray tracing efficiency is low due to the fact that the number of planes in the space is large.
Drawings
FIG. 1 is a flow chart of a method of back ray tracing in a first embodiment of the present invention;
FIG. 2 is a schematic diagram of a second embodiment of an apparatus for back ray tracing of the present invention;
FIG. 3 is a schematic diagram of a process for determining an effective reflecting surface in a third embodiment of the present invention;
fig. 4 is a schematic diagram of a determination process of an ineffective reflecting surface in a third embodiment of the present invention.
Detailed Description
In order to solve the following problems in the prior art: when the inverse ray tracing algorithm is realized, the calculation process is very complex and the ray tracing efficiency is low due to more planes in the space; the present invention provides a method and an apparatus for back ray tracing, which will be described in further detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
The first embodiment of the present invention provides a method for back ray tracing, the flow of which is shown in fig. 1, including steps S102 to S104:
s102, determining effective reflecting surfaces in all reflecting surfaces in a preset indoor space according to a preset rule, wherein the effective reflecting surfaces are reflecting surfaces capable of reflecting;
and S104, determining the position of the terminal to be positioned based on all the effective reflecting surfaces according to a back ray tracing algorithm and a virtual mirror image point algorithm.
The embodiment of the invention determines the effective reflecting surfaces in all the reflecting surfaces in the preset indoor space according to the preset rule, and then calculates and processes based on all the effective reflecting surfaces, thereby greatly reducing the number of the reflecting surfaces to be tracked in the preset space, greatly reducing the calculated amount, improving the ray tracking efficiency and solving the following problems in the prior art: when the inverse ray tracing algorithm is implemented, the calculation process is very complex and the ray tracing efficiency is low due to the fact that the number of planes in the space is large.
In the process of determining effective reflecting surfaces in all reflecting surfaces in a preset indoor space according to a preset rule, whether other intersection points with a first preset object exist between line segments connected with the center points of the preset planes of the first preset object or not needs to be judged; and if no other intersection points exist, determining the plane where the central point is located as an effective reflecting surface. Of course, correspondingly, if there are other intersection points, it can be determined that the plane where the central point is located is an invalid reflecting surface, and the invalid reflecting surface is a reflecting surface corresponding to the valid reflecting surface and not to be considered subsequently.
In the process of judging whether other intersection points with the first predetermined object exist between line segments connected with the center points of the predetermined planes of the first predetermined object, a space rectangular coordinate system can be established for a predetermined indoor space; then, determining the space coordinates of the network element, the space coordinates of each vertex included by each plane of the first predetermined object and the plane equation of each plane of the first predetermined object in the established space rectangular coordinate system; determining the spatial coordinates of the central point corresponding to each plane according to the spatial coordinates of each vertex of each plane; establishing a linear equation of the central point and the network element according to the spatial coordinate of the central point and the spatial coordinate of the network element; and finally, judging whether other intersection points with the first preset object exist on a line segment corresponding to the linear equation where the central point and the network element are located. Through the process, the relation between the network element and any object in the preset indoor space can be simply established, and the operation process is simple.
After determining the invalid reflection surface and the valid reflection surface of an object, it is necessary to see whether the object is blocked or shields other objects, and the like, and therefore, it is also necessary to determine whether the same plane equation exists in the plane equation of each plane of the first predetermined object and the plane equation of each plane of the second predetermined object.
In the case of the existence of the same plane equation, it is stated that two objects have a plane next to each other, and therefore, one plane of one of the objects may be occluded, and therefore, it is necessary to acquire the vertex space coordinates of each of the two planes having the same plane equation; judging whether the space coordinates of each vertex of the effective reflecting surfaces in the two planes are in the range of the space coordinates of each vertex of the other plane; and in the case that each vertex space coordinate of the effective reflecting surface is in the range of each vertex space coordinate of another plane, the effective reflecting surface is determined as the ineffective reflecting surface again.
After the effective reflecting surfaces are determined, the position of the terminal to be positioned can be determined based on all the effective reflecting surfaces according to a back ray tracing algorithm and a virtual mirror image point algorithm, and the process is as follows: determining a plurality of reflection paths between the terminal to be positioned and each network element according to the virtual mirror image point algorithm and each effective reflection surface in sequence; synthesizing a plurality of reflection paths between each network element and the terminal to be positioned into a synthesized reflection path according to a predetermined synthesis algorithm; under the condition that the terminal to be positioned has four synthesized reflection paths, the position of the terminal to be positioned can be determined according to the network element positions corresponding to the four synthesized reflection paths by a back ray tracing algorithm.
A second embodiment of the present invention provides an inverse ray tracing apparatus, which is schematically shown in fig. 2, and includes: the determining module 10 is configured to determine an effective reflecting surface of all reflecting surfaces in a predetermined indoor space according to a predetermined rule, where the effective reflecting surface is a reflecting surface that can be reflected; and the positioning module 20 is coupled with the determining module 10 and is used for determining the position of the terminal to be positioned according to the back ray tracing algorithm and the virtual mirror image point algorithm based on all the effective reflecting surfaces.
The determining module 10 is specifically configured to: judging whether other intersection points with the first predetermined object exist between line segments connected with the center points of the predetermined planes of the first predetermined object; and under the condition that other intersection points do not exist, determining the plane where the central point is located as an effective reflecting surface.
In implementation, the determining module 10 is specifically configured to: establishing a space rectangular coordinate system for a preset indoor space; determining the space coordinates of the network element, the space coordinates of each vertex included by each plane of the first predetermined object and the plane equation of each plane of the first predetermined object in the established space rectangular coordinate system; determining the spatial coordinates of the central point corresponding to each plane according to the spatial coordinates of each vertex of each plane; establishing a linear equation of the central point and the network element according to the spatial coordinate of the central point and the spatial coordinate of the network element; and the judging unit is used for judging whether other intersection points with the first preset object exist on the line segment corresponding to the linear equation where the central point and the network element are located.
Further, the determining module 10 may be further configured to determine whether the plane equation of each plane of the first predetermined object and the plane equation of each plane of the second predetermined object have the same plane equation; under the condition that the same plane equation exists, acquiring respective vertex space coordinates of two planes with the same plane equation; judging whether the space coordinates of each vertex of the effective reflecting surfaces in the two planes are in the range of the space coordinates of each vertex of the other plane; and in the case that each vertex space coordinate of the effective reflecting surface is in the range of each vertex space coordinate of another plane, the effective reflecting surface is determined as the ineffective reflecting surface again.
The positioning module 20 is specifically configured to: determining a plurality of reflection paths between the terminal to be positioned and each network element according to the virtual mirror image point algorithm and each effective reflection surface in sequence; synthesizing a plurality of reflection paths between each network element and the terminal to be positioned into a synthesized reflection path according to a predetermined synthesis algorithm; and under the condition that the terminal to be positioned has four synthesized reflection paths, determining the position of the terminal to be positioned according to the network element positions corresponding to the four synthesized reflection paths according to a reverse ray tracing algorithm.
Based on the above description of the embodiments, those skilled in the art can appreciate that the above mentioned back ray tracing apparatus may exist as a stand-alone device, which may be a separate storage medium when configured, and that the above mentioned determining module and the locating module may be integrated into a processor of the device and implemented in the form of program code.
A third embodiment of the invention provides a preprocessing method for back ray tracing. Under the condition that the positions and the number of the network elements are not changed, only one pretreatment is needed, the invisible surface of the object is deleted, the reflecting surfaces (refraction and diffraction in the same way) calculated in the positioning process are reduced, and the ray tracking efficiency can be greatly improved; meanwhile, the method can effectively eliminate invalid reflecting surfaces and accelerate ray tracking. The method comprises the following steps:
step 1: firstly, a space rectangular coordinate system is established for an indoor space. The vertex at the rear end of the left side of the house is taken as a coordinate origin O, the direction in which the origin O points to the south is taken as the positive direction of an X coordinate axis, the direction in which the origin O points to the west is taken as the positive direction of a Y coordinate axis, and the reverse direction in which the origin O points to the geocentric is taken as the positive direction of a Z coordinate axis.
Step 2: an attribute tuple a ═ B, C is established for an arbitrary object Ω (assumed to be a hexahedron) in a room, where B is a set of plane equations of 6 faces of the hexahedron, and C is a set of four vertices included in each face of the hexahedron.
And step 3: the spatial coordinates of the network elements (which are transmitting signals in space and become network elements, mostly base stations) are determined.
And 4, step 4: the position of the center point of each face of the hexahedron is determined, with the coordinates E ═ x1, y1, z 1.
And 5: after the central coordinates of each surface are determined, the linear equation of the central point of each surface and the network element is calculated, and which surface of the object is the effective reflecting surface is judged through a plane visible method.
The plane visible method comprises the following steps: determining the value range of coordinates of four vertexes in each surface of the object, and respectively solving the central point of any one surface and the intersection points which are possibly existed in the six surfaces of the object and the linear equation determined by the network element; if the intersection point is in the range of four vertexes of any one of the six surfaces, continuously judging whether other intersection points are located on the object on a line segment of the direction of the point pointing to the network element; if not, the plane where the central point is located is a visible effective reflecting surface; otherwise, it is an invisible ineffective reflecting surface.
Step 6: the visible faces each network element and each object has are recorded.
In the implementation process, it is also necessary to see whether the object is blocked or blocks other objects, and therefore, the following processing procedures are also required:
step 1: and judging whether the plane equations of any surfaces of any two objects are equal or not. If so, executing step 2; otherwise, step 5 is executed.
Step 2: and acquiring the vertex coordinates of the two planes, and calculating the areas of the two planes.
And step 3: and comparing the space coordinate of each point in the plane with the maximum value and the minimum value of the corresponding x coordinate, y coordinate and z coordinate in all the points of the plane with the larger area. In the implementation process, if the two areas are equal, one plane is randomly taken as a plane with a smaller area for judgment.
And 4, step 4: if all the points in the surface with the smaller area satisfy the condition that the x coordinate, the y coordinate and the z coordinate are all larger than or equal to the minimum value of the x coordinate, the y coordinate and the z coordinate in the object with the larger area and are smaller than or equal to the maximum value of the x coordinate, the y coordinate and the z coordinate, the plane with the smaller area is judged to be an invalid reflecting surface, and the plane with the smaller area is deleted. Otherwise, it is an effective reflection surface. In the implementation process, whether the plane with the smaller area is an effective reflecting surface or not is judged again.
And 5: and (6) ending.
In the embodiment, under the condition that the positions and the number of the network elements are not changed, only one preprocessing is needed, and the ray tracking efficiency can be greatly improved; and invalid reflecting planes can be effectively eliminated, and the ray tracing speed is increased.
The above process is described in detail with reference to the accompanying drawings.
As shown in fig. 3, which is composed of an arbitrary object Ω and a network element Q, the house is omitted in fig. 3.
Firstly, a space rectangular coordinate system is established for an indoor space, the vertex of the rear end of the left side of the house is taken as a coordinate origin O, the direction in which the origin O points to the south is taken as the positive direction of an X coordinate axis, the direction in which the origin O points to the west is taken as the positive direction of a Y coordinate axis, and the reverse direction in which the origin O points to the earth center is taken as the positive direction of a Z coordinate axis. An attribute tuple a ═ (B, C) is established for any object Ω in the room, where B is a set of plane equations for 6 faces of the hexahedron, and C is a set of four vertices contained in each face of the hexahedron.
According to the spatial position of the indoor object (assumed to be hexahedron) and the network element, determining the spatial coordinates of each vertex of the object and the network element, and assuming that the vertex Ai is (Ai (x), Ai (y), Ai (z)) and the coordinate of the network element Q is (Q1, Q2, Q3). Finding the central point position of each face of the hexahedron and determining the coordinate assumed central point Bi ═ (Bi (x), Bi (y), b (z)).
After the central coordinates of each surface are determined, the linear equation of the central point of each surface and the network element is calculated, assuming that the linear equation of the central point Bi and the network element Q is Li, taking a straight line L1 as an example, a straight line L1 intersects the plane A1A4A7a6 at a point B1 and also intersects the bottom surface A1A2A3A4 at a point S. Because the B1 point coordinate falls within the plane A1A4A7a6 (noting the minimum value greater than the corresponding coordinate and less than the maximum value of the corresponding coordinate), and no other intersection points on the line segment of B1Q fall on the object, the plane in which the center point B1 lies is a visible, effectively reflective surface. Meanwhile, taking the straight line L5 as an example, the straight line L5 intersects the plane A1A2A3A4 at B5, and also intersects the plane A1A4A7a6 at S1, and the B5 coordinate falls within the plane A1A2A3A4 (note that the minimum value of the corresponding coordinate is greater than the maximum value of the corresponding coordinate is smaller than the minimum value of the corresponding coordinate). However, there is an intersection point S1 on the line B5Q, which indicates that the plane A1A2A3a4 in which the center point is located is an invisible ineffective reflection surface.
As shown in fig. 4, which contains two objects, the network element on the side close to the object 2, the house is omitted in fig. 4.
Firstly, whether plane equations of any surfaces of any two objects in the room are equal or not is judged. In this example, the face A3B3C3D4 of the object 1 is the same as the face ABCD of the object 2, and the vertex coordinates of the two planes are acquired, and the areas of the two planes are calculated. The area of the object 1 is smaller than the object 2 in this example.
The spatial coordinates of each point in the object of plane A3B3C3D4 are then compared to the maximum and minimum values of the corresponding x, y, and z coordinates in the object of the larger area plane ABCD. In this example, all points in the plane A3B3C3D4 satisfy that the x, y, and z coordinates are equal to or greater than the minimum and equal to or less than the maximum of the x, y, and z coordinates in the face ABCD object, so the plane A3B3C3D4 is determined to be an ineffective reflecting surface and deleted.
Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (such as a mobile phone, a computer, a server, or a network device) to execute the above embodiments of the present invention.
Optionally, in this embodiment, the storage medium may include, but is not limited to: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes. Optionally, in this embodiment, the processor executes the method steps described in the above embodiments according to the program code stored in the storage medium. Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation manners, and this embodiment is not described herein again. It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, and the scope of the invention should not be limited to the embodiments described above.
Claims (8)
1. A method of back ray tracing, comprising:
determining an effective reflecting surface in all reflecting surfaces in a preset indoor space according to a preset rule, wherein the effective reflecting surface is a reflecting surface capable of reflecting;
determining the position of a terminal to be positioned based on all effective reflecting surfaces according to a reverse ray tracing algorithm and a virtual mirror image point algorithm;
wherein, the effective reflecting surface of all reflecting surfaces in the preset indoor space is determined according to a preset rule, and the method comprises the following steps:
judging whether other intersection points with the first predetermined object exist between line segments connected with the center point of the predetermined plane of the first predetermined object;
and under the condition that other intersection points do not exist, determining the plane where the central point is located as an effective reflecting surface.
2. The method of claim 1, wherein determining whether there are other intersections between the line segment connecting the network element and the center point of the predetermined plane of the first predetermined object with the first predetermined object comprises:
establishing a space rectangular coordinate system for a preset indoor space;
determining the space coordinates of the network element, the space coordinates of each vertex included in each plane of the first predetermined object and the plane equation of each plane of the first predetermined object in the established space rectangular coordinate system;
determining the spatial coordinates of the central point corresponding to each plane according to the spatial coordinates of each vertex of each plane;
establishing a linear equation of the central point and the network element according to the spatial coordinate of the central point and the spatial coordinate of the network element;
and judging whether other intersection points with the first preset object exist on a line segment corresponding to the linear equation where the central point and the network element are located.
3. The method of reverse ray tracing of claim 2, said method further comprising:
judging whether the plane equation of each plane of the first predetermined object and the plane equation of each plane of the second predetermined object have the same plane equation or not;
under the condition that the same plane equation exists, acquiring respective vertex space coordinates of two planes with the same plane equation;
judging whether the space coordinates of each vertex of the effective reflecting surfaces in the two planes are in the range of the space coordinates of each vertex of the other plane;
and under the condition that each vertex space coordinate of the effective reflecting surface is in the range of each vertex space coordinate of the other plane, the effective reflecting surface is determined as an ineffective reflecting surface again.
4. The method of anyone of claims 1 to 3 wherein determining the position of the terminal to be positioned based on all active reflecting surfaces according to a back ray tracing algorithm and a virtual mirror point algorithm comprises:
determining a plurality of reflection paths between the terminal to be positioned and each network element according to each effective reflection surface in sequence according to a virtual mirror image point algorithm;
synthesizing a plurality of reflection paths between each network element and the terminal to be positioned into a synthesized reflection path according to a preset synthesis algorithm;
and under the condition that the terminal to be positioned has four synthesized reflection paths, determining the position of the terminal to be positioned according to the network element positions corresponding to the four synthesized reflection paths by a back ray tracing algorithm.
5. An inverse ray tracing apparatus, comprising:
the device comprises a determining module, a judging module and a judging module, wherein the determining module is used for determining effective reflecting surfaces in all reflecting surfaces in a preset indoor space according to a preset rule, and the effective reflecting surfaces are reflecting surfaces which can be reflected;
the positioning module is used for determining the position of the terminal to be positioned based on all effective reflecting surfaces according to a reverse ray tracing algorithm and a virtual mirror image point algorithm;
wherein the determining module is specifically configured to:
judging whether other intersection points with the first predetermined object exist between line segments connected with the center point of the predetermined plane of the first predetermined object, and determining that the plane where the center point is located is an effective reflecting surface under the condition that other intersection points do not exist.
6. The backward ray tracing apparatus of claim 5, wherein the determining module is specifically configured to:
establishing a space rectangular coordinate system for a preset indoor space;
determining the space coordinates of the network element, the space coordinates of each vertex included in each plane of the first predetermined object and the plane equation of each plane of the first predetermined object in the established space rectangular coordinate system;
determining the spatial coordinates of the central point corresponding to each plane according to the spatial coordinates of each vertex of each plane;
establishing a linear equation of the central point and the network element according to the spatial coordinate of the central point and the spatial coordinate of the network element;
and judging whether other intersection points with the first preset object exist on a line segment corresponding to the linear equation where the central point and the network element are located.
7. The backward ray tracing apparatus of claim 6, wherein the determination module is further configured to:
judging whether the plane equation of each plane of the first predetermined object and the plane equation of each plane of the second predetermined object have the same plane equation or not;
under the condition that the same plane equation exists, acquiring respective vertex space coordinates of two planes with the same plane equation;
judging whether the space coordinates of each vertex of the effective reflecting surfaces in the two planes are in the range of the space coordinates of each vertex of the other plane;
and under the condition that each vertex space coordinate of the effective reflecting surface is in the range of each vertex space coordinate of the other plane, the effective reflecting surface is determined as an ineffective reflecting surface again.
8. The backward ray tracking apparatus of any of claims 5-7, wherein the positioning module is specifically configured to:
determining a plurality of reflection paths between the terminal to be positioned and each network element according to each effective reflection surface in sequence according to a virtual mirror image point algorithm;
synthesizing a plurality of reflection paths between each network element and the terminal to be positioned into a synthesized reflection path according to a preset synthesis algorithm;
and under the condition that the terminal to be positioned has four synthesized reflection paths, determining the position of the terminal to be positioned according to the network element positions corresponding to the four synthesized reflection paths by a back ray tracing algorithm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710016359.1A CN108286968B (en) | 2017-01-10 | 2017-01-10 | Method and device for tracing back ray |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710016359.1A CN108286968B (en) | 2017-01-10 | 2017-01-10 | Method and device for tracing back ray |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108286968A CN108286968A (en) | 2018-07-17 |
| CN108286968B true CN108286968B (en) | 2021-11-09 |
Family
ID=62819407
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710016359.1A Active CN108286968B (en) | 2017-01-10 | 2017-01-10 | Method and device for tracing back ray |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108286968B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104112293A (en) * | 2014-07-04 | 2014-10-22 | 南京航空航天大学 | Ray tracing acceleration algorithm applied to tunnel environment |
| CN104330788A (en) * | 2014-10-30 | 2015-02-04 | 中国人民解放军信息工程大学 | Radio location method based on reach path reverse tracking |
| CN104573368A (en) * | 2015-01-13 | 2015-04-29 | 北京航空航天大学 | Surface element projection based triangular cross-sectional ray tube electromagnetic ray tracing algorithm |
| CN106209264A (en) * | 2015-05-08 | 2016-12-07 | 富士通株式会社 | The method for tracing in electromagnetic wave propagation path, device and system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101205719B1 (en) * | 2009-10-29 | 2012-11-28 | 한국전자통신연구원 | 3D Preprocessing Method For Ray Tracing |
-
2017
- 2017-01-10 CN CN201710016359.1A patent/CN108286968B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104112293A (en) * | 2014-07-04 | 2014-10-22 | 南京航空航天大学 | Ray tracing acceleration algorithm applied to tunnel environment |
| CN104330788A (en) * | 2014-10-30 | 2015-02-04 | 中国人民解放军信息工程大学 | Radio location method based on reach path reverse tracking |
| CN104573368A (en) * | 2015-01-13 | 2015-04-29 | 北京航空航天大学 | Surface element projection based triangular cross-sectional ray tube electromagnetic ray tracing algorithm |
| CN106209264A (en) * | 2015-05-08 | 2016-12-07 | 富士通株式会社 | The method for tracing in electromagnetic wave propagation path, device and system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108286968A (en) | 2018-07-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112771573B (en) | Depth estimation method and device based on speckle images and face recognition system | |
| Geok et al. | A comprehensive review of efficient ray-tracing techniques for wireless communication | |
| JP6645346B2 (en) | Method, apparatus and system for tracking electromagnetic wave propagation path | |
| US20110153294A1 (en) | Method of three dimensional ray tracing in the dynamic radio wave propagation environment | |
| US8463024B1 (en) | Combining narrow-baseline and wide-baseline stereo for three-dimensional modeling | |
| EP3530026B1 (en) | Method and system for radio communication network planning | |
| CN113607185B (en) | Lane line information display method, lane line information display device, electronic device, and computer-readable medium | |
| CN114627239B (en) | Bounding box generation method, device, equipment and storage medium | |
| CN110210564B (en) | Similar house type detection method and device | |
| WO2019105194A1 (en) | Propagation path search method and apparatus | |
| CN108286968B (en) | Method and device for tracing back ray | |
| CN116912817A (en) | Three-dimensional scene model splitting method and device, electronic equipment and storage medium | |
| CN115511701A (en) | Method and device for converting geographic information | |
| CN113867371B (en) | Path planning method and electronic equipment | |
| CN113470161B (en) | Illumination determination method for volume cloud in virtual environment, related equipment and storage medium | |
| CN113313809A (en) | Rendering method and device | |
| US10846909B2 (en) | Portable ray tracing apparatus | |
| CN114565721A (en) | Object determination method, device, equipment, storage medium and program product | |
| Liao et al. | Multipath Cluster‐Assisted Single Station Localization Based on SSA‐GA in Outdoor NLOS Environment | |
| Chen et al. | A parallel multipoint viewshed analysis method for urban 3D building scenes | |
| Tsoukalos et al. | Attempting to reconstruct a 3D indoor space scene with a mobile device using ARCore | |
| CN117119160B (en) | Projection control method and device, electronic equipment and storage medium | |
| CN108062793A (en) | Processing method, device, equipment and storage medium at the top of object based on elevation | |
| US10924195B2 (en) | Bounced ray tubes with preprocessing of visibility | |
| CN110889902B (en) | Three-dimensional modeling method and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |